Some known image forming apparatuses, such as printers, copying machines, and multifunction devices, include an electromagnetic clutch on a route for transmitting a driving force from a drive source, e.g., a motor, to a driving member, e.g., a conveying roller for conveying a sheet. In such a configuration, transmission and interruption of a driving force from the motor to the conveying roller is implemented by activation and deactivation, respectively, of the electromagnetic clutch.